STABLE ION STUDIES OF THE CHRYSENE SKELETON - PROTONATION OF CHRYSENE, 6-HALOCHRYSENES, 6-ACETYLCHRYSENE, AND 4H-CYCLOPENTA[DEF]CHRYSENE - NMR-STUDIES OF CHARGE-DISTRIBUTION IN CHRYSENIUM CATIONS AND AM1 CALCULATIONS

Chrysene (1), 6-fluorochrysene (2), 6-chlorochrysene (3), and 6-bromoc hrysene (4) are cleanly monoprotonated in FSO3H . SbF5 (ca. 10:1)/SO2C lF at the C-12 position. 6-Acetylchrysene (5) is CO-protonated in FSO3 H/SO2ClF with significant charge delocalization into the chrysene and provides a model for a C-6-protonated chrysenium cation. 4H-Cyclopenta [def]chrysene (6) is protonated at C-5 (site of bromination and acetyl ation). The observed chrysenium (methanochrysenium) cations are those predicted by AM1 to have the lowest energies. The NMR characteristics of the resulting arenium ions are discussed and the he Delta delta Cs- 13 are compared with AM1 calculated changes in charges [Delta q(c) = q (c)(ion) - q(c)(neutral)]. Possible relationships between the charge d elocalization path in chrysenium ions and metabolic activation of chry senes by electrophilic pathways via the bay-region epoxide ring openin g (--> PAH-DNA adduct) are evaluated.